Elucidation of the Pyridine Ring-Opening Mechanism of 2,2'-Bipyridine or 1,10-Phenanthroline Ligands at Re(I) Carbonyl Complexes

The cleavage of the C-N bonds of aromatic heterocycles, such as pyridines or quinolines, is a crucial step in the hydrodenitrogenation (HDN) industrial processes of fuels in order to minimize the emission of nitrogen oxides into the atmosphere. Due to the harsh conditions under which these reactions take place (high temperature and H2 pressure), the mechanism by which they occur is only partially understood, and any study at the molecular level that reveals new mechanistic possibilities in this area is of great interest. Herein, we unravel the pyridine ring-opening mechanism of 2,2'-bipyridine (bipy) and 1,10-phenanthroline (phen) ligands coordinated to the cis-{Re(CO)2(N-RIm)(PMe3)} (N-RIm= N-alkylimidazole) fragment under mild conditions. Computational calculations show that deprotonation of the pyridine ring, once dearomatized, is crucial to induce ring contraction, triggering extrusion of the nitrogen atom from the ring and cleavage of the C-N bond. It is noteworthy that different products (regioisomers) are obtained depending on whether the ligand used is bipy or phen due to the additional rigidity and stability conferred by the central ring of the phen ligand, an issue also addressed and clarified computationally. Strong support for the proposed mechanism is provided by the characterization and isolation, including three single-crystal X-ray diffraction structures, of several of the proposed reaction intermediates.

Effects of Lipids and Type of Amino Acid in Protein in Microalgae on Nitrogen Reaction Pathways during Hydrothermal Liquefaction

It is meaningful to understand the conversion pathways of nitrogen during the hydrothermal liquefaction process of microalgae to reveal the related reaction mechanisms and develop effective methods to prevent N from ending in biocrude, which eventually increases the quality of biocrude. Extending from our previous works that mainly focused on two high-protein (>50 wt%) microalgae (Chlorella sp. and Spirulina sp.), Nannochloropsis sp., which has a high lipid content (>70 wt%), was used as the feedstock for this project using the same methodology. The high lipid content in Na. induced less nitrogen during the oil phase and as a result, reduced the heteroatom content while also improving the quality of biocrude. It is worth noting that another investigation was conducted on the model compounds with different types of amino acids to specify the effects of the types of amino acids in the proteins in microalgae on the N pathway and their distribution in the products (aqueous phase, oil, solid, and gas). It was found that the basic amino acid in microalgae caused the formation of more N-heterocyclic compounds in the biocrude. The mass flow based on the mass balance was demonstrated to further refine the map showing the predicted reaction pathway of nitrogen from the previous version.

Competitive Hydrodeoxygenation and Hydrodenitrogenation Reactions in the Hydrotreatment of Fatty Acid and Amine Mixtures

Understanding how hydrotreating oxygen-containing compounds together with nitrogen-containing compounds affects the reactivity and selectivity is relevant for processing renewable feedstocks. In this work, competitive hydrodeoxygenation (HDO) and hydrodenitrogenation (HDN) reactions were studied by co-hydrotreating palmitic acid (C16 acid) and tetradecylamine (C14 amine) over a Pt/ZrO2 catalyst in a batch reactor. HDO proceeded faster than HDN in the studied system, and the deoxygenation reactions were found to have an inhibitory effect on HDN. Co-hydrotreating the C16 acid and the C14 amine expanded the reaction network from the individual HDO and HDN networks and changed the prevailing reaction pathways, initially in favor of oxygen removal. The formation of heavy secondary amides and amines through condensation reactions became increasingly favored as the share of C16 acid in the feed increased. For a given conversion level, the condensation product selectivity was observed to increase as the reaction temperature was decreased, whereas increasing the reaction temperature promoted the formation of the desired paraffins. This work described the ease of HDO compared to HDN, the role of condensation reactions in the co-hydrotreating reaction network, and the inhibitory effect on HDN thereof.

Reactivity of Sulfur and Nitrogen Compounds of FCC Light Cycle Oil in Hydrotreating over CoMoS and NiMoS Catalysts

NiMoS and CoMoS catalysts were synthesized and applied to hydrotreating (HDT) of FCC light cycle oils (FCC-LCO) in an autoclave batch reactor at 613 K and 8.6 MPa H2. The S and N compounds in LCO were classified into four and three groups, respectively, in terms of the HDT reactivity. The individual and the competitive reactivities of the S and N compounds in the HDS and the HDN were investigated over the conventional CoMoS and NiMoS catalysts using S and N model compounds (dibenzothiophene, DBT, and carbazole, CBZ). In the HDS of DBT, both the direct desulfurization (DDS) and pre-hydrogenation pathway (HYD) were found to proceed, whereas the HYD pathway was favored for the HDN of CBZ. As a result, the NiMoS catalyst that facilitates the HYD pathway showed better activity in the HDN of LCO than the CoMoS (k = 10.20 × 10−2 vs. 1.80 × 10−2 h−1). Indeed, the HDS of LCO over the NiMoS was more favorable than that over the CoMoS catalyst (k = 4.3 × 10−1 vs. 3.6 × 10−1 h−1).

Sequential Extraction and Characterization of Nitrogen Compounds after Hydrothermal Liquefaction of Sewage Sludge

Organic solid wastes such as sewage sludge are potential feedstocks for the production of drop-in biofuels. Hydrothermal liquefaction (HTL) is a process that converts the wet sewage sludge into an organic biocrude. To fulfill industrial fuel standards, the considerable heteroatom content of the biocrude needs to be lowered by downstream processes. Nitrogen (N) contained in several compounds poses a challenge and yet, the complex chemical composition of HTL-biocrude samples has hindered detailed analysis and understanding. In particular, N-containing aromatic substances appear very persistent in biocrude. In the present work, two alkaline (NaHCO₃ and NaOH) and one acidic (HCL) aqueous solutions were subsequently applied to extract and recover polar N-containing compounds from the biocrude matrix with an N-content of 3.8 wt %. Gas chromatography-mass spectrometry, atmospheric pressure chemical ionization in positive mode, and Fourier transform ion cyclotron resonance mass spectrometry were applied for their characterization and results show that a large share of N-compounds with an aromatic, pyridinic structure was found in the acidic extracted fraction with an N-content of 9.5 wt %. Aliphatic N-compounds were less affected by the separation and ended in the residual fraction. N-compounds with multiple oxygen functionalizations are enriched in the alkaline extracted fractions. This showed that N-compounds with an aromatic structure are strongly affected by polar groups and can potentially be extracted by downstream processes with appropriate solvents.

A Highly Active NiMoAl Catalyst Prepared by a Solvothermal Method for the Hydrogenation of Methyl Acrylate

In this study, a series of Ni10MoxAl composite metal oxide (Ni10MoxAl, NiO = 10 wt.%, x = 2.5, 5, 10, 15, 20 wt.%) catalysts with different Mo content were prepared by a solvothermal method using a water—ethanol system. By employing various characterization technologies, it was confirmed that the suitable amount of the Mo element can not only promote the dispersion of the Ni species but also inhibit the formation of the inactive NiAl2O4 phase. Consequently, the hydrogenation activity of the Ni10MoxAl catalysts was affected by the particle size of the active components and the amount of the NiAl2O4 phase. As a result, the Ni10Mo10Al catalyst showed the best catalytic performance on methyl acrylate hydrogenation, and the yield of methyl propionate can be increased from 53.7% to 89.5% at 100 °C and 1 MP H2, compared with the Ni10Mo10/γ–Al2O3 catalyst prepared by a traditional impregnation method. The stability of the Ni10Mo10Al catalyst was also investigated, and the catalyst can run stably for 23 h. The novel strategy adopted in this article provides a new direction for the preparation of high activity Ni–Mo catalysts.

Investigating the Effects of Organonitrogen Types on Hydrodearomatization Reactions over Commercial NiMoS Catalyst

The hydrogenation of polyaromatic compounds (PACs) present in mineral oils is of great importance when it comes to the desired product properties and the minimization of health hazards; however, the presence of organonitrogen inhibits the conversion of these compounds. In this study, the inhibition effects of different types of organonitrogen compounds (acridine (ACR) and carbazole (CBZ)-basic and nonbasic organonitrogen) on the hydrodearomatization (HDA) of phenanthrene over a sulfided commercial NiMo/Al2O3 catalyst were investigated in a microflow trickle-bed reactor at a temperature range of 280 to 320 °C and at a total pressure of 120 barg. Analysis of the experimental results shows that the hydrogenation of phenanthrene is significantly decreased in the presence of organonitrogen, with acridine showing stronger inhibiting effects. The extent of hydrodenitrogenation (HDN) is shown to correlate with the inhibition degree with a higher extent of HDN being achieved for carbazole than for acridine. Results from co-feeding different nitrogen types (acridine and carbazole) indicate that basic nitrogen is the dominating type of organonitrogen inhibitor. Recovery of catalyst activity in the absence of organonitrogen indicates fully reversible deactivation suggesting that inhibition relates to competitive adsorption and slower reaction rate of HDN compared to HDA.

In-depth characterization of nitrogen heterocycles of petroleum by liquid chromatography-energy-resolved high resolution tandem mass spectrometry

With the increased attention to processing heavy crude oils, a detailed description of chemical composition is critical for the petroleum refining industry. The current analytical technique such as ultrahigh resolution mass spectrometry has been successfully applied for the molecular level characterization of complex petroleum fractions. But the structural characterization of heavy petroleum feedstock is still a great challenge. In this study, a novel in-depth characterization method of nitrogen heterocycles (N-heterocycles) in heavy petroleum mixtures was proposed by online liquid chromatography coupled with electrospray ionization high resolution energy-resolved mass spectrometry. A series of typical basic aromatic, neutral aromatic and naphtheno-aromatic nitrogen heterocyclic model compounds were synthesized to investigate energy-resolved fragmentation behaviors in high energy collision-induced dissociation at 10-100 eV. Energy-dependent fragmentation pathways were elucidated. Notably, characteristic double bond equivalent (DBE) versus carbon number distributions of N₁ ions and all CH ions were discovered, which were closely related to their core structure. Then a workflow to assign core structures of alkyl-substituted N-heterocycles in petroleum was proposed and validated. The developed method was applied to investigate the structural isomers in feed and product vacuum gas oil (VGO) fractions. Core structural differences in feed VGO and subtle structural variations between feed and product VGOs were recognized. This work can distinguish structural isomers of N-heterocycles with the subtle difference in their core structure in heavy petroleum fractions based on global energy dimensional fragmentation characteristics.

Assessing the feasibility of chemical recycling via steam cracking of untreated plastic waste pyrolysis oils: Feedstock impurities, product yields and coke formation

Chemical recycling of plastic waste to base chemicals via pyrolysis and subsequent steam cracking of pyrolysis oils shows great potential to overcome the limitations in present means of plastic waste recycling. In this scenario, the largest concern is the feasibility. Are plastic waste pyrolysis products acceptable steam cracking feedstocks in terms of composition, product yields and coke formation? In this work, steam cracking of two post-consumer plastic waste pyrolysis oils blended with fossil naphtha was performed in a continuous bench-scale unit without prior treatment. Product yields and radiant coil coke formation were benchmarked to fossil naphtha as an industrial feedstock. Additionally, the plastic waste pyrolysis oils were thoroughly characterized. Analyses included two dimensional gas chromatography coupled to a flame ionization detector for the detailed hydrocarbon composition as well as specific analyses for heteroatoms, halogens and metals. It was found that both pyrolysis oils are rich in olefins (∼48 wt%) and that the main impurities are nitrogen, oxygen, chlorine, bromine, aluminum, calcium and sodium. Steam cracking of the plastic waste derived feedstocks led to ethylene yields of ∼23 wt% at a coil outlet temperature of 820 °C and ∼28 wt% at 850 °C, exceeding the ethylene yield of pure naphtha at both conditions (∼22 wt% and ∼27 wt%, respectively). High amounts of heavy products were formed when steam cracking both pyrolysis oils, respectively. Furthermore, a substantial coking tendency was observed for the more contaminated pyrolysis oil, indicating that next to unsaturated hydrocarbons, contaminants are a strong driver for coke formation.

Hydrogenation of Pyridine and Hydrogenolysis of Piperidine overγ-Mo2N Catalyst: A DFT study

Increasing demands on producing environmentally friendly products are becoming a driving force for designing high active catalysts. Thus, surfaces that efficiently catalyse the nitrogen reduction reactions are vastly sought in moderating air-pollutant emissions. This contribution aims to computationally investigate the hydrodenitrogenation (HDN) networks of pyridine over γ-Mo2N(111) surface via density functional theory (DFT) approach. Various adsorption configurations have been considered for the molecularly adsorbed pyridine. Findings indicate that pyridine can be adsorbed via side-on and end-on modes in six geometries in which one adsorption site is revealed to have the lowest adsorption energy of (-45.3 kcal/mol(. Over nitrogen hollow site adsorption site, initial HDN steps proceed by the stepwise hydrogenation of pyridine into piperidine followed the Langmuir−Hinshelwood mechanism. The obtained findings are the first to theoretically model the hydrogenation pathways of pyridine to form piperidine then the hydrogenolysis of piperidine producing C5H12 and NH3 over metal nitride and paved the way for further investigations to better understanding such an important nitrogen removal reactions.

Removal of Pyridine, Quinoline, and Aniline from Oil by Extraction with Aqueous Solution of (Hydroxy)quinolinium and Benzothiazolium Ionic Liquids in Various Ways

Based on above background, quinolinium, 8-hydroxy-quinolinium, and benzothiazolium ionic liquids, containing the acidic anions of methanesulfonate ([CH3SO3]−), phosphate ([H2PO4]−), p-toluenesulfonate ([p-TSA]−), and bisulfate ([HSO4]−) were synthesized. After comparison, the aqueous solution of benzothiazole bisulfate [HBth][HSO4] was selected as the most ideal extractant for removing pyridine and aniline. Meanwhile, benzothiazole bisulfate [HBth][HSO4] solution was found as the best one for removing quinoline from simulated oil. Then, the single stage extraction and two-step extraction were used in the extraction for the simulated oil containing pyridine, quinoline or aniline, and their mixture, respectively. Their denitrogenation performance on their N-removal effect was compared on the basis of structural features, and main extraction conditions were further investigated, including mass ratio of IL to water, mass ratio of IL to oil, and temperature. Furthermore, the extraction process was described by two kinetic equations. Recovery and reuse of IL were realized by back-extraction and liquid-liquid separation, and a related mechanism was speculated, according to all the experimental results. Finally, based on the developed method for preparing complex adsorbent tablets, corresponding immobilized IL was used to remove target objects, by solid phase extraction, in order to extend separation ways, which was more easily recovered after extraction.

Ni-Catalyzed Iterative Alkyl Transfer from Nitrogen Enabled by the In Situ Methylation of Tertiary Amines

Current methods to achieve transition-metal-catalyzed alkyl carbon-nitrogen (C-N) bond cleavage require the preformation of ammonium, pyridinium, or sulfonamide derivatives from the corresponding alkyl amines. These activated substrates permit C-N bond cleavage, and their resultant intermediates can be intercepted to affect carbon-carbon bond-forming transforms. Here, we report the combination of in situ amine methylation and Ni-catalyzed benzalkyl C-N bond cleavage under reductive conditions. This method permits iterative alkyl group transfer from tertiary amines and demonstrates a deaminative strategy for the construction of Csp³-Csp³ bonds. We demonstrate PO(OMe)₃ (trimethylphosphate) to be a Ni-compatible methylation reagent for the in situ conversion of trialkyl amines into tetraalkylammonium salts. Single, double, and triple benzalkyl group transfers can all be achieved from the appropriately substituted tertiary amines. Transformations developed herein proceed via recurring events: the in situ methylation of tertiary amines by PO(OMe)₃, Ni-catalyzed C-N bond cleavage, and concurrent Csp³-Csp³ bond formation.

A perspective on hydrothermal processing of sewage sludge

The US annually produces 79 million dry tons of liquid organic waste including sewage sludge. Anaerobic digestion can only reduce the sludge volume by 50% in mass, leaving the other half as a growing waste management and hygienic problem. Hydrothermal processing (HTP), a set of several chemical digestion processes, could be used to convert sewage sludge into valuable products and minimize potential environmental pollution risks. Specifically, hydrothermal carbonization and hydrothermal liquefaction have been extensively studied to sustainably manage sludge. Two of the main reasons for this are the high upscalability of HTP for public waste management and that it is estimated that HTP can recover eleven times more energy from waste products than landfilling. An integration of HTP with anaerobic digestion or recycling the soluble organics (in the HTP aqueous products) into the HTP process could lead to a higher overall rate of energy recovery for municipal sewage sludge.

Utilisation of poultry industry wastes for liquid biofuel production via thermal and catalytic fast pyrolysis

The objective of this study was to examine the potential of poultry wastes to be used as feedstock in non-catalytic and catalytic fast pyrolysis processes, which is a continuation of our previous research on their conversion into biofuel via slow pyrolysis and hydrothermal conversion. Both poultry meal and poultry litter were examined, initially in a fixed bed bench-scale reactor using ZSM-5 and MgO as catalysts. Pyrolysis of poultry meal yielded high amounts of bio-oil, while pyrolysis of poultry litter yielded high amounts of solid residue owing to its high ash content. MgO was found to be more effective for the deoxygenation of bio-oil and reduction of undesirable compounds, by converting mainly the acids in the pyrolysis vapours of poultry meal into aliphatic hydrocarbons. ZSM-5 favoured the formation of both aromatic compounds and undesirable nitrogenous compounds. Overall, all bio-oil samples from the pyrolysis of poultry wastes contained relatively high amounts of nitrogen compared with bio-oils from lignocellulosic biomass, ca. 9 wt.% in the case of poultry meal and ca. 5-8 wt.% in the case of poultry litter. This was attributed to the high nitrogen content of the poultry wastes, unlike that of lignocellulosic biomass. Poultry meal yielded the highest amount of bio-oil and was selected as optimum feedstock to be scaled-up in a semi-pilot scale fluidised bed biomass pyrolysis unit with the ZSM-5 catalyst. Pyrolysis in the fluidised bed reactor was more efficient for deoxygenation of the bio-oil vapours, as evidenced from the lower oxygen content of the bio-oil.

Effect of Cobalt Catalyst Confinement in Carbon Nanotubes Support on Fischer-Tropsch Synthesis Performance

Pre-treating the multi-walled carbon nanotubes (CNTs) support by refluxing in 35 vol% nitric acid followed by heating at the temperature of 600 to 900 °C resulted in the formation of defects on the CNTs. Increasing the temperature of the pre-treatment of the CNTs from 600 °C to 900 °C, enhanced the fraction of cobalt-oxide nanoparticles encapsulated in the channels of CNTs from 31% to 70%. The performance of Co/CNTs in Fischer-Tropsch synthesis (FTS) was evaluated in a fixed-bed micro-reactor at a temperature of 240 °C and a pressure of 2.0 MPa. The highest CO conversion obtained over Co/CNTs.A.900 was 59% and it dropped by ~3% after 130 h of time-on-stream. However, maximum CO conversion using Co/CNTs.A.600 catalysts was 28% and it decreased rapidly by about 54% after 130 h of time-on-stream. These findings show that the combined acid and thermal pre-treatment of CNTs support at 900 °C has improved the stability and activity of the Co/CNTs catalyst in FTS.

Hydrotreatment of bio-oil distillates produced from pyrolysis and hydrothermal liquefaction of duckweed: A comparison study

A comprehensive comparison of hydrothermal liquefaction (HTL) to the pyrolysis of duckweed was conducted to determine the yields and components of the crude bio-oils and their distillates. The upgrading behaviors of the distillates were thoroughly investigated with the use of used engine oil as a solvent. With all other variables fixed, HTL produced crude bio-oil with a lower H/C ratio (1.28 ± 0.03) than pyrolysis did (1.45 ± 0.04). However, its distillates had a higher H/C ratio (1.60 ± 0.05) and total yield (66.1 ± 2.0 wt%) than pyrolysis (1.46 ± 0.04 and 47.2 ± 1.4 wt%, respectively). Phenolics and nitrogenous heterocycles constituted relatively major proportions of the two crude bio-oils and most of their distillates. Obvious differences in molecular composition between the two crude bio-oils and their distillates were ascribed to the distinct impacts of HTL and pyrolysis and were affected by the distillate temperature. Co-hydrotreating with used engine oil (UEO) provided the upgraded bio-oils much higher H/C ratios (~1.78 ± 0.05) and higher heating values (~45.5 ± 1.4 MJ·kg^-1), as well as much lower contents of N, O and S compared to their initial distillates. Aromatics and alkanes constituted a large proportion in most of upgraded bio-oils. N removal from the pyrolysis distillates was easier than from the HTL distillates. Distinct differences in yields and molecular compositions for the upgraded bio-oils were also attributed to the different influences associated with the two conversion routes.

Prediction model of biocrude yield and nitrogen heterocyclic compounds analysis by hydrothermal liquefaction of microalgae with model compounds

The model of biocrude yield and the nitrogen heterocyclic compounds in biocrude of microalgae hydrothermal liquefaction are two of the most concerned issues in this field at present. This study explored a hydrothermal liquefaction biocrude yield model involved in the interaction among biochemical compounds in microalgae and analysed nitrogen heterocyclic compounds in biocrude. The model compound (castor oil, soya protein and glucose) and Nanochloropsis were liquefied at 280°C for 1h. The products were analyzed by GC-MS, element analysis and FTIR. The results suggested that interactions among different components in microalgae enhanced biocrude yield. The biocrude yield prediction model involved cross-interactions performed more accurate than previous models.When the ratio of protein and carbohydrate around 3, the cross-interaction and nitrogen heterocyclic compounds in biocrude would both reach the highest extent.

Hydrodenitrogenation of pyridines and quinolines at a multinuclear titanium hydride framework

Investigation of the hydrodenitrogenation (HDN) of aromatic N-heterocycles such as pyridines and quinolines at the molecular level is of fundamental interest and practical importance, as this transformation is essential in the industrial petroleum refining on solid catalysts. Here, we report the HDN of pyridines and quinolines by a molecular trinuclear titanium polyhydride complex. Experimental and computational studies reveal that the denitrogenation of a pyridine or quinoline ring is easier than the ring-opening reaction at the trinuclear titanium hydride framework, which is in sharp contrast with what has been reported previously. Hydrolysis of the pyridine-derived nitrogen-free hydrocarbon skeleton at the titanium framework with H2O leads to recyclization to afford cyclopentadiene with the generation of ammonia, while treatment with HCl gives the corresponding linear hydrocarbon products and ammonium chloride. This work has provides insights into the mechanistic aspects of the hydrodenitrogenation of an aromatic N-heterocycle at the molecular level.

Molecular titanium nitrides: nucleophiles unleashed

Reactivity studies of a rare example of a molecular titanium nitride are presented. A combination of theory and NMR spectroscopy provide a description of the bonding in the these nitrides, the role of the counter cation, K⁺, as well as the origin of their highly downfield ¹⁵N NMR spectroscopic shifts.

In this contribution we present reactivity studies of a rare example of a titanium salt, in the form of [μ₂-K(OEt₂)]₂[(PN)₂Ti Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> N]₂ (1) (PN^– = N-(2-(diisopropylphosphino)-4-methylphenyl)-2,4,6-trimethylanilide) to produce a series of imide moieties including rare examples such as methylimido, borylimido, phosphonylimido, and a parent imido. For the latter, using various weak acids allowed us to narrow the pK_a range of the NH group in (PN)₂TiNH to be between 26–36. Complex 1 could be produced by a reductively promoted elimination of N₂ from the azide precursor (PN)₂TiN₃, whereas reductive splitting of N₂ could not be achieved using the complex (PN)₂Ti Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> NNTi(PN)₂ (2) and a strong reductant. Complete N-atom transfer reactions could also be observed when 1 was treated with ClC(O)^tBu and OCCPh₂ to form NC^tBu and KNCCPh₂, respectively, along with the terminal oxo complex (PN)₂TiO, which was also characterized. A combination of solid state ¹⁵N NMR (MAS) and theoretical studies allowed us to understand the shielding effect of the counter cation in dimer 1, the monomer [K(18-crown-6)][(PN)₂TiN], and the discrete salt [K(2,2,2-Kryptofix)][(PN)₂TiN] as well as the origin of the highly downfield ¹⁵N NMR resonance when shifting from dimer to monomer to a terminal nitride (discrete salt). The upfield shift of ¹⁵N_nitride resonance in the ¹⁵N NMR spectrum was found to be linked to the K⁺ induced electronic structural change of the titanium-nitride functionality by using a combination of MO analysis and quantum chemical analysis of the corresponding shielding tensors.

A study on the origin of the active sites of HDN catalysts using alumina-supported MoS3 nanoparticles as a precursor

The origin of the active sites of the hydrodenitrogenation catalysts was comprehensively studied using alumina-supported MoS₃ nanoparticles (NPs) as a novel precursor.

The role of oxygen functional groups in the adsorption of heteroaromatic nitrogen compounds

A wood-based activated carbon (AC) was oxidized using different oxidants. The resultant adsorbents were applied to adsorb nitrogen (N) containing compounds that appeared in light cycled oil. Appropriate oxidation treatment can increase oxygen functional groups on the surface of AC without much damage to its pore structure. Oxygen functional groups play a key role in enhancing adsorptive selectivity of carbons. Lactone groups can facilitate the selective removal of 1-ring N compounds. Phenolic groups, total CO2-releasing groups and total O groups show an improvement in the adsorption of 2-ring N compounds. Aldehyde groups favor the adsorption of 3-ring and 4-ring N compounds. However, excessive oxidation can result in the collapse of pore structure and closure of pore channels. For instance, the carbon oxidized by a mixture of concentrated H2SO4 and HNO3 has an extremely low adsorption performance.

Mononuclear and Terminally Bound Titanium Nitrides

The Ti(III) azido complex (PN)2Ti(N3) (PN(-) = (N-(2-(diisopropylphosphino)-4-methylphenyl)-2,4,6-trimethylanilide), can be reduced with KC8 to afford the nitride salt [μ2-K(OEt2)]2[(PN)2Ti≡N]2 in excellent yield. While treatment of the dimer with 18-crown-6 yields a mononuclear nitride, complete encapsulation of the alkali metal with cryptand provides the terminally bound nitride as a discrete salt [K(2,2,2-Kryptofix)][(PN)2Ti≡N]. All complexes reported here have been structurally confirmed and also spectroscopically, and the Ti-Nnitride bonding has been probed theoretically via DFT-based methods.

Super adsorption capability from amorphousization of metal oxide nanoparticles for dye removal

Transitional metal oxide nanoparticles as advanced environment and energy materials require very well absorption performance to apply in practice. Although most metal oxides are based on crystalline, high activities can also be achieved with amorphous phases. Here, we reported the adsorption behavior and mechanism of methyl blue (MB) on the amorphous transitional metal oxide (Fe, Co and Ni oxides) nanoparticles, and we demonstrated that the amorphousization of transitional metal oxide (Fe, Co and Ni oxides) nanoparticles driven by a novel process involving laser irradiation in liquid can create a super adsorption capability for MB, and the maximum adsorption capacity of the fabricated NiO amorphous nanostructure reaches up to 10584.6 mgg⁻¹, the largest value reported to date for all MB adsorbents. The proof-of-principle investigation of NiO amorphous nanophase demonstrated the broad applicability of this methodology for obtaining new super dyes adsorbents.